AIR POLLUTION:

Manufacturers of heavy-duty diesel engines have slashed emissions from new engines by more than 90 percent for most pollutants, according to a study released yesterday.

New pollution control technologies that were developed in response to U.S. EPA regulations have led to the steep declines in pollution, according to the study. For several major pollutants, emissions were reduced even more steeply than federal law required.

"The important message is to see how clean these diesel engines are," said Joe Suchecki, a spokesman for the Engine Manufacturers Association. The technologies that have been developed "are just working tremendously well, and they're very effective in reducing the [particulate matter] and all the hydrocarbons and the air toxics to near zero levels," he said.

The report is the first phase of a five-year study directed by the Health Effects Institute and conducted by the Coordinating Research Council. The study was sponsored by a range of groups, including the Energy Department, EPA, the Engine Manufacturers Association and the American Petroleum Institute.

EPA's 2001 highway diesel rule required manufacturers to steeply cut engine emissions of soot- and smog-forming pollutants for engines sold after January 2007. The rules apply to heavy-duty highway engines, such as those used in trucks and buses.

Researchers found that emissions of fine particulate matter, or soot, were about 99 percent lower than soot emissions allowed from engines manufactured in 2004. Soot emissions were also 90 percent lower than the new 2007 standard requires. Pollution from carbon monoxide, hydrocarbons and a number of air toxics had also declined by more than 90 percent since 2004 levels and was significantly lower than required levels, the report says.

"The manufacturers outdid themselves in over-complying with the standards for carbon monoxide, hydrocarbons and particulate matter," said Dan Greenbaum, president of the Health Effects Institute, an independent research organization funded jointly by EPA and industry.

NOx emissions were about 70 percent lower than past levels and 10 percent below the EPA requirement. Manufacturers will be required to slash NOx output by another 80 percent for engines sold after Jan. 1, 2010.

"Obviously we have work to do on the NOx standard, which is coming up at the end of this year, and engine manufacturers are in the process of getting that technology developed and available," Suchecki said.